The present disclosure relates generally to turbine engines and, more specifically, to systems and methods of controlling rotor blade clearance in a centrifugal compressor of a turbine engine.
Known turbine engines experience several different phases of operation including, but not limited to, start-up, warm-up, steady-state, shutdown, and cool-down. At least some known turbine engines include rotating compressors and turbines that define clearances between rotor blades and inner surfaces of the surrounding seal members. These clearances are controlled to facilitate improving operating efficiency. Such clearances generally vary as the turbine or compressor transitions from one operational phase to another. More particularly, each operational phase has different operating conditions associated with it, such as temperature, pressure, and rotational speed, which will induce changes in the clearances between components, including static and moving components within the turbine engine.
In at least some known turbine engines, the clearances between compressor and/or turbine rotor blades and the seal members are also controlled to prevent contact-related damage therebetween as the turbine and compressor transitions between operational phases. For example, in at least some known turbine engines, cold, or assembly, clearances are set to be no larger than required for steady-state operation to account for thermal and mechanical differences in the turbine engine when transitioning between phases of operation. Moreover, as described above, turbine engine efficiency depends at least in part on the clearance between tips of the rotating blades and seal members coupled to the surrounding stationary components. If the clearance is too large, enhanced gas flow may unnecessarily leak through the clearance gaps, thus decreasing the turbine engine's efficiency. Many known turbines and compressors include variable clearance mechanisms in the high-pressure turbine section, the low-pressure turbine section, and the compressor section. However, it is generally difficult to implement clearance control systems that are integrally formed with the turbine and compressor due to the complex geometry of the components and manufacturing limitations.